A quick look at a scatter plot that charts rear legroom against luxury sedan MSRPs reveals a dearth of spacious bargains – few, if any, luxury sedans offer exceptionally spacious rear accommodations at a relatively low starting price. To fill the vacuum, Infiniti has made its Q70 available in a Q70L variant – in English, long wheelbase – for 2015.

The artist formerly known as the Infiniti M has been available in stretched-out form in the Chinese market for two years, and the US introduction is accompanied by several updates that include slightly reworked styling cues, and refinements to the drivetrain and chassis. The Q70L's wheelbase extends 5.9 inches (with a commensurate expansion of knee room), while overall length increases to 202 inches, a 7.3-inch bump. Powertrain options include a 3.7-liter V6 which produces 330 horsepower and 270 pound-feet of torque (starting at $51,350), or a 5.6-liter V8 that yields 420 hp and 417 lb-ft (and climbs to $64,550). The long-wheelbase treatment adds $1,500 to Q70 MSRPs. Not surprisingly, the Hybrid version is not available with the L treatment.

Up to three Q70L rear passengers are treated to reading lamps, a 12-volt power outlet, rear door close assist, and available heated seats. Unlike its Far Eastern counterpart (and competitors like the $61,500 Hyundai Equus), the US-spec Q70L's rear seats don't recline. Bummer.

What to make of this stretched Infiniti that's just 1.2 inches of legroom shy of an S-Class? The Q70 has never quite compared dynamically to the Mercedes-Benz E-Class or BMW 5 Series, and the longer wheelbase makes it even harder for the Japanese sedan to compete when it comes to driving satisfaction. What the Q70L does offer, however, are rather plush interior accommodations that include available semi-analine leather and Japanese Ash trim that's been bedazzled by sprinklings of genuine silver mixed into the lacquer.

A test drive of the 2015 Infiniti Q70L through New York City and into the sinewy roads leading to Bear Mountain revealed even greater rifts between the lengthened sedan and its sporty competitors. Where does this leave Infiniti's Q70L amidst the macrocosm of luxury sedans, which include the Audi A6, Cadillac CTS, and Jaguar XF?

Driving Notes

Lengthening the wheelbase adds approximately 100 pounds of mass to the Q70L's curb weight, the equivalent of throwing a skinny kid in the back seat, give or take a few cheeseburgers. It's not a significant increase in tonnage, but the longer body makes the L variant feel noticeably less nimble than the standard-issue Q70, aided by the fact that the steering ratio has not been altered.

Ride quality felt somewhat busy but controlled over NYC's notoriously irregular pavement, while rural roads outside of Manhattan revealed a more sedate side to the sedan's damping.

The Q70L's cabin is pleasantly quiet, thanks in part to active noise canceling technology and new-for-2015 improvements including added insulation and better seals. There's still a faint but noticeable engine induction sound, which lends an air of sportiness to the aural experience.

At least visually speaking, the Q70L's driving experience is all about the curves. Two humps dominate the instrument cluster, which is framed by the hood's bulbous profile. Arcs of wood and leather bind the interior, and the center stack is distinguished by its wave-like shape.

The Q70L is all about the expanded rear seating area, and a stint in its aft compartment revealed plenty of space, but a disappointing lack of amenities. Legroom is indeed generous, though the passenger experience doesn't feel particularly special. Unlike Hyundai's Equus, the Infiniti doesn't have a panel of controls that make the back perch feel like a first-class airline throne. The seats can be heated but not cooled, and they don't recline.

Perhaps this stretched-out five-seater will gain traction within that obscure segment of the population that would rather be chauffeured in midlevel luxury, rather than take the wheel themselves. We're a bit hazy on this rather specific target demographic, which seems more likely to reside in a Shanghai suburb than in a major metropolitan US city, but suppose the Q70L's sales figures will be the ultimate measure of its success.

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